This invention relates generally to methods and apparatus for controlling cooling fans for electronic equipment such as computers.
It would be desirable to have the option of deploying a single computer as either a server or a workstation. One of the challenges in doing so is that workstation computers need to be quiet under normal circumstances because they are typically located near users in an office environment. Server computers on the other hand need to be as reliable as possible. Consequently, fans inside server computers arc typically run at higher speeds than are those within workstation computers. The higher fan speed provides better cooling and therefore better longevity for the components inside the enclosure. But higher fan speeds create noise, and so are problematic in workstations.
A dual-purpose computer according to the invention has a gravity-actuated switch mounted therein or thereon. The gravity-actuated switch is used to control the speed of a cooling fan for the computer. When the computer is operated in a horizontal orientation such as a typical rack-mounted server would be, the gravity actuated switch assumes a first state. When the computer is operated in a vertical orientation such as a typical desk side workstation would be, the gravity actuated switch assumes a second state. When the switch is in the first state, fan speed controller circuitry runs the fan at a first speed. When the switch is in the second state, fan speed controller circuitry runs the fan at a second speed. In one embodiment, the first speed is a higher speed intended to optimize reliability, and the second speed is a lower speed intended to minimize noise.